probes::basefork(3)

NAME
probes::basefork - Yet Another Base Class for implementing SmokePing Probes

OVERVIEW
Like probes::basevars, but supports the probe-specific property `forks' to determine how many processes should be run concurrently.

SYNOPSYS
 *** Probes ***

 + MyForkingProbe
 # run this many concurrent processes
 forks = 10

 + MyOtherForkingProbe
 # we don't want any concurrent processes at all for some reason.
 forks = 1

DESCRIPTION
Not all pinger programs support testing multiple hosts in a single go like fping(1). If the measurement takes long enough, there may be not enough time perform all the tests in the time available. For example, if the test takes 30 seconds, measuring ten hosts already fills up the SmokePing default five minute step.

Thus, it may be necessary to do some of the tests concurrently. This module defines the ping method that forks the requested number of concurrent processes and calls the pingone method that derived classes must provide.

The pingone method is called with one argument: a hash containing the target that is to be measured. The contents of the hash are described in probes::basevars(3pm).

The number of concurrent processes is determined by the probe-specific variable `forks' and is 5 by default. If there are more targets than this value, another round of forks is done after the first processes are finished. This continues until all the targets have been tested.

There is a timeout in which each child has to finish. This is determined by the Smokeping global database step and the `forks' variable:

timeout = <step> / ceiling(<# of targets> / <forks>)

If the child isn't finished when the timeout occurs, it will be killed along with any processes it has started.

AUTHOR
Niko Tyni <ntyni@iki.fi>

BUGS
The timeout code has only been tested on Linux.

SEE ALSO
probes::basevars(3pm), probes::EchoPing(3pm)